The immunologic disorders, idiopathic thrombocytopenic purpura (ITP), lupus erythromatosis, neonatal-, post-transfusion-, and drug-purpura have been further studied with respect to determining pathophysiologic mechanisms, cellular response to immune reactions, improved techniques for diagnosis and prognosis and fundamental immunochemical reactions of significance in disease states. These studies are also pertinent to disorders involving autoimmunity, isoimmunization, and transplantation immunity; and to mechanisms of cellular secretion.